For convenience and efficiency, or for purely medical reasons, it is appropriate to administer plural solutions or fluids intravenously to a patient through a single venal entry. Often the fluids or solutions are referred to as primary and secondary solutions, and this process is commonly known in the industry as intravenously piggy-back administration.
Intravenous piggy-back administration is described, for example, in a brochure entitled "New Concepts In Intermittent IV Therapy", published by Travenol Laboratories, Inc., Deerfield, Ill. Typically such a piggy-back IV set will include two upper Y-legs or branches with each line being communicatively connected to either the primary or secondary solution container. The Y-legs will lead from the solution container to a Y-connector. Communicatively connected at the Y-connector is a delivery line that leads therefrom and which is operative to convey the fluid or solution to the patient. A check valve is normally placed in one of the upper Y-legs or lines, typically in the line leading from the primary solution container. The gravitational head of the secondary fluid in the secondary container acts to close the check valve to prevent flow from the primary container. Such a system will deliver the secondary solution to the patient first, and then after the secondary container has been emptied, flow will automatically start from the primary fluid since the check valve automatically opens once the secondary container has emptied.
To monitor and control the administration of both the primary and secondary solutions, there is typically provided a drip chamber between each solution container and the respective upper Y-leg or line. During administration, a drop count controller, typically of the electric eye type, is placed into operative association with the particular drip chamber in the operative line.
Once the first solution container has emptied, and the second container starts to deliver fluid or solution in the other upper Y-leg or line, a nurse or aide must change the drop count controller to another chamber disposed in the other upper Y-leg or line. This obviously requires time on the part of the nurse or aide and actually requires that the total administration process be closely observed and watched in order that proper flow control can be maintained throughout the entire process.
In addition to the time and effort required of the nurse or aide in supervising and managing the intravenous piggy-back administration, the nurse or aide must be careful that air bubbles do not collect and exist beyond either of the respective drip chambers, which essentially involves the entire IV set.